Neither Yélian nor Caelian can express it the way English does as both languages lack an infinitive and a gerund. Yélian basically says "I only ever really loved it, that was when I hurt you", adding a temporal component. In Caelian, a special structure takes place that is only ever possible with the auxillary verb byanglis (here with its 3SG>3SG form byäis). Its object is basically an entire sentence: "The only thing that I ever really loved, that was the {I hurt you}."

Heaven and Earth, but I feel the color of the cake when you keep the Victoria.
I had a mantra on the moss and I had to go to bed.